Various types of electrical connectors include an electrical contact socket having an open end for receiving a pin, such as a terminal pin, to form an electrical connection between the socket and the pin. One type of contact socket commonly has been termed a wire-trap socket, wherein a wire or a pin easily is inserted into the socket but is difficult to be removed therefrom.
For instance, a wire-trap electrical contact socket may have a plurality of inwardly projecting resilient tongues extending axially of the socket with free ends of the tongues directed away from the open pin-receiving end of the socket. Therefore, a pin easily can be inserted into the socket, simply by deflecting the tongues away from the open end of the socket, i.e., in the insertion direction of the pin. If an attempt is made to pull the pin out of the socket, the free ends of the tongues resist such removal. Commonly, if it is necessary to remove a pin from such a socket, removal is facilitated by twisting or rotating the pin in a sort of screw fashion. In fact, the tongues might score the outside of the pin in a spiral fashion. If the pin cannot be rotated sufficiently, removal can be facilitated by twisting the pin back and forth while pulling on the pin.
However, there are certain environments wherein electrical contact sockets of the character described above have proven deficient because the pin is capable of working its way out of the socket. Such environments normally involve vibrations of the electrical connection. For instance, the pin might be a component of an appliance, such as a pin of a heating element in a dishwasher, wherein the electrical connection between the pin and the socket constantly is exposed to vibrations. Effectively, the pin works its way out of the socket, similar to the above-described action of twisting or rotating the pin back and forth, in response to the vibrations.
This invention is directed to solving the above problems by providing an electrical contact socket which prevents a pin from backing out of its socket even under conditions of vibration by preventing unintentional rotation of the pin relative to the socket.